Electric circuit interrupter



March 16, 1954 w. E. PAUL 2,672,541

ELECTRIC CIRCUIT INTERRUPTER Filed Dec. 2'7, 1951 IMSM/IT/fl/Y 29 o o 29as 6 5 1 40 32 1 a9 46- 45L... 4755: 48 1 I 38 Z7 44 43 26 a L z 25 24Inventor; William 15. Paul,

His A51: orney.

Patented Mar. 16, 1954 ELECT-RIC CIRCUIT IN'ZIERRUP'IER William E. Paul,Schenectady, N. Y., assignor to General Electric Company, a corporationof New York Application December 27, 1951, Serial No. 263,616

14 Claims.

'My invention relates to electric circuit interrupters and, moreparticularly, to a blast control arrangement for used in conjunctionwith circuit interrupters of the fluid-blast type.

In circuit breakers of the gas or liquid blast type, it is the presentpractice to separate the contacts and to supply :a blast of fluid suchas gas or liquid to the space in which the arc is drawn for the purposeof aiding in the extinguishment or the arc. No provision is made inpresent breaker constructions for controlling the particular instant atwhich the blast is supplied to the are relative to the instantaneousalternating current value thereof. Thus if the tinstantaneous value ofcurrent is of a high order of magnitude at the particular instant whenthe blast is supplied to'the arc, there will be a tendency for the gasor liquid to choke the breaker since the presence of the high currentare raises the pressure of the fluid and interferes with the exhaustthereof from the interrupting chamber. Since the blast supplied to theare is normally ineifective to extinguish the arc until a current zeroof the alternating current wave occurs, it is logical that moreefiicient interruption could be accomplished suitable fluid controlmeans were provided for directing a blast at the are only when theinstantaneous current is at or approaching a zero value.

A principal object of this invention is "to provide fluid blastcontrolling means for use in conjunction with electric circuit breakerswhich blasts the are only when the current is at or approaching a zeroinstantaneous value.

Another object of this invention is to improve the interruptingperformance and capacity of circuit breakers by preventing the chokingof the breaker due to a blast of fluid supplied prematurely to theint-errupting chamber.

A further object of this invention is to provide an improved circuitinterrupter wherein suitable venting means relieves the pressuregenerated within the interrupting chamber due to the formation of an arctherein and wherein a cross blast is directed at the arc to extinguishthe arc at or near a current zero.

Th invention in one form as applied to a fluid blast circuit breakerhaving normally closed valve means arranged to control the fluid blastcomprises resilient energy-storing means biasing the valve means towardthe open position, magnetic holding means respcnsive to theinstantaneous magnitude of current through the breaker for opposing theaction of the resilient means,

and mechanical restraining means normally cperative to maintain thevalve closed is released in response to :an opening operation of "thebreaker so as to place the valve means briefly under the control of theresilient means and the magnetic means. When the instantaneous value ofcurrent approaches a small value or becomes zero, the resilientenergy-storing means overcome the action of the magnetic holding meansso as to open the valve means thereby to supply a blast of fluid to thearc and to effect its extinguishment. According to one feature of theinvention, a movable one of the contacts is of a hollow construction andhence serves as a pressure-relieving vent for pressure built up withinthe interrupting unit due to the presence of the arc therein after thecontacts have separated and before the valve means has opened. Accordingto still another feature of the invention, the hollow contact isoperated through a tubular operating rod by the operating mechanismthereby to facilitate the direct venting of such excessive arc-generatedpressures.

While the invention is described herein in conjunction with a circuitinterrupter of the gas blast type, it will be understood that it is notlimited to such a circuit breaker and that the principles thereof arealso applicable to interrupters of the liquid blast type.

For a better understanding of my invention; reference may be had to thefollowing description taken in conjunction with the accompanying drawingin which Fig. 1 is a side view partially in section of a gas blastcircuit breaker embodying the invention and in which Fig. 2 is a Viewalong the line 2-2 of Fig. 1.

With reference to Fig. 1, which may be considered as being a single poleelement of a multiple pole air blast breaker, a frame structure orhousing I is supported upon bushing type in sulators 2. Mounted on theframe structure I is a pressure reservoir 3 to which is connected ablast conduit 4 having therein a valve 5. Conduit 4 is connected to theinterrupting unit generally designated by the numeral E5. interrupterunit 6 is provided with an inlet port "I and an outlet port 8 and thearcing chamber 9 formed within the interrupter unit 5 contains fixedcontact elements it and a tubular hollow movable contact element '1 I.Arc divider means 12 is disposed downstream from the outlet 8. Anexhaust conduit l3 leads from the outlet 8 to the expansion chamber Mwhich dissipates the heated arc vapors to atmosphere through the louversi5. Interrupting unit 6 and parts associated therewith is of the generaltype disclosed in Patent 3 2,453,317 to Dell K. Tower et al., grantedJanuary 4, 1949, and assigned to the assignee of this invention.

An adapter member I3 is aiiixed to the upper end of the tubular contactII so as to afford a connection between contact I I and an insulatingtubular operating rod I! which is in communication with an expansionchamber I3 which dissipates to atmosphere through the louvers I5.

For the purpose of operating the tubular contact I I by means of itsassociated tubular operating rod II, a pair of connecting rods or linksI9 are pivotally connected at 20 to the front and rear of the tubularexhaust member I! and are pivotally connected at 2i to the front andrear operating crank arms 22 which are secured to and rotatable with anoperating shaft 23, which may, of course, carry other similar cranks forthe other two poles of the breaker, only th rear crank 22 being shown inthe drawing. Rotation of shaft 23 and opening of valve could be effectedby an operating mechanism of the type disclosed in Patent 2,436,191 toJulius W. Timmerman, Jr., granted February 17, 1948, and assigned to theassignee of this application. Since the particular operating mechanismfor reciprocating the tubular contact I I and for opening the valve 5forms no part of the present invention, the details of this structurehave been omitted from the drawing for the sake of simplicity.

As is indicated in Fig. l, the inlet port 1 and the outlet port 8 arerespectively closed by gate valve members 24 and 25. While both theinlet and outlet ports I and 8 are shown provided with valves such as 24and 25, it will be understood that it is within the province of theinvention to us only one such valve. For example, the principles of theinvention would be applicable if only the gate valve 24 were utilized.

Both the gat valves 24 and 25 are mechanically coupled through theplatelike cross head 23 which encircles the tubular contact II and towhich is connected at either side thereof a ver tically disposed valvelift rod 21. This pair of valve lift rods 21 is normally biaseddownwardly toward the valve closed position by the mechanicalrestraining means comprising compressional springs 28 and plungermembers 29 each having a shoulder 29a and disposed for verticalreciprocation through openings 30 formed in a housing structure 3|secured to each side of the tubular exhaust operating member I1 in anysuitable manner. Each plunger 29 engages, but is separ2131; from theassociated valve operating rod 2! a External connection to the movablecontact I I is afforded by the terminal conductor 33 disposed within abushing 34 constructed of insulating material and secured in anysuitable manner to the frame I. nected by a conventional conductor studwhich is disposed within the insulating bushing 2,

In accordance with one feature of th invention, the conductor 33 issplit longitudinally into two parallel current-carrying parts. an upperpart 35 which is fixed in position within the insulating bushing 34 anda lower resilient part 3'! which constitutes the resilient stored energymeans for operating the valve. A fixed contact block 38 is secured tothe upper fixed part 35 of the conducting stud 33 by any suitabl meanssuch as by the weld indicated at 39. The tubular contact II isreciprocable within an opening formed in the fixed contact block 38 andis ar- The fixed contact ill is com 4 l J ranged in sliding contacttherewith, e. g. comparable to the method disclosed in Patent 2,283,657to Thumim which is assigned to the assignce of this invention. Formaking the split bushing stud constitute an effectiveparallelcurrent-path conductor, a strip of insulating material 4idivides the upper fixed part 35 from the lower resilient part 31, beingpreferably secured to the fixed leg 35 of the stud by means of asuitable cement.

At this point, it should be understood that the bifurcated stud 33 ispreferably of some good electrically conducting metal or alloy havingresiliency such, e. g. as beryllium copper. The stud may be assumed tobe of square section and fitting into bushing 34 which has a square-sewtioned bore. Further, the resilient leg 31 normally lies flat andhorizontal along the bottom of the bore, but is shown in its flexedupward position in Fig. 1 which, as will later become evident,corresponds to the valve-closed position. In other words, the flexiblearm 3'! of the bushing stud 33"constitutes spring means biasing theblast control valves 24 and to their open position. From the drawings itwill be seen that an extension arm 42 is secured to opposite sides ofthe left-hand end of flexible portion 3'! of conductor stud 33 by bolts43 or by any other suitable means. As is clearly indicated in Fig. 2 thepair of arms 42 widely embrace the conducting contact block 38 which issuitably recessed at 44 to accommodate the angle bends of the armsduring their flexing movement with the resilient stud leg 31. Pivotallyconnected to the left-hand ends of the arms 42 at 45 are a pair oflevers 46 which are supported at their mid-points by a fixed pivot 41mounted on the contact block 38. Each of the levers 46 is pivoted at 43to one of the valve lift rods 21. Extension 42 is electrically connectedwith the contact block 38 by means of a flexible strap 40.

From the description above, it will be understood that the circuitthrough the breaker comprises the terminal of conductor 33, parallelconductors and 31 of the bushing stud 33 including conducting strap 40,contact block 38, tubular contact II, fixed contacts I0, and theconducting stud of the electric bushing 2,

From the above description, it will be obvious that the spring means 28through the plungers 29 normally hold the valve lift rods 21 and thevalves 24 and 25 downwardly to the closed position so that when thebreaker is closed, as shown in the drawings, the valves 24 and 25 areclosed since the springs 28 are constructed to preponderate over thevalve-operating spring means constituted by the resilient stud leg 31.

'When the main blast valve5 is opened and when operating crank 23 isrotated clockwise as viewed in Fig. 1, pressure gas is supplied throughconduit 4 to valve 24 and simultaneously the tubular contact I I ismoved upwardly just to take up the contact wipe and then to draw an arcbetween its arcing tip and the fixed finger contacts I0. Such an arcwill develop heat and pressure within the arcing chamber 9 and, untilthe valve '24 and 25 open, such ionized are products are vented upwardlythrough the tubular contact I I, the tubular operating member I I, theexpansion chamber I8 and diffuse through the louvers [5 to atmosphere.After the initial upward movement of tubular contact II has taken up thecontact wipe so that the contacts are in the act of separating,theshoulder 29a. of the plunger 9 is picked up by the lower end of the Iaccuser housing 31 so that the plungers 2-9 may move up out ofengagement withthe valve rods 21. Ks previously mentioned, the springs28 preponderate over the upward lift of the valve-operating resilientleg 31 so that not until after sepnation of the plungers from the valverods 2-! do the valves 24 and 25 come under the control of thecurrent-carrying resilient leg 3'? and-parts associated therewith.

"Since the spring leg 31 normally is biasing the valves 2! and S25upwardly, these valves will open unless held momentarily in the closedposition by a greater opposing force due to the electromagneticattraction between theparallel currentcarrying paths of upper part 35and the lower leg 31'o'f conductor 33 which is induced during :p'ortionsof the alternating current wave when the instantaneous current value isin excess at a predetermined value. Such electro-magnetic interactionbetween a pair of closely-coupled parallel current paths through whichcurrent flows in the same direction so as to produce an attractive forcetherebetween is well known. Furthermore, the -condi-ictors and thetubular contact I! form a right-angled eledtro-magnetic loop circuitwhich inherently tends to expand as is Well known. Thus a component ofthis magnetic loop force acts upwardly on the part :91 and thereioreaugments the aforesaid elective-magnetic par-a1- lel-curre'nt effecttending to hold the valve memi Thus, when the alternating currentapproaches an instan'taneous zero value, these electro mag netic holdingforces decrease proportionately so that the spring force of leg 31 willbecome eifective to open the blast control valves 24 and 25 foranticipating the approaching current 'zero. Accordingly, a sudden crossblast of cool unionizcd arc-extinguishing air or gas is directed acrossthe separated contacts at the most favorable in figuration of thetubular ope-rating rod H and cranks 2 2 in Fig. '1.

Upon closure o'ithe break-er, the operating shaft 2c is rotatedcounterclockwise turn, causes the tubular operating rod l the tubularcontact ll to move downwardly. such time during the closing movement asthe lower ends of plungers '2'9 engage the upper ends of valve lift rods'21, the preponderating springs 28 will become effective to close thevalves 2s and 25 against the bias of their opening spring constituted bythe resilient leg 3"! and, as the closing movement proceeds, this actionwill be fol lowed by the compression of the ,preponderating springs 28due to the relative upward movement of the plungers 2%] within theirhousings 31 as the hollow contact [I travels down through its wipedistance into the fixed contact fingers 40.

While I have shown and described a, particular embodiment of theinvention, 1 do not wish to be limited thereto and intend in theappended claims to cover all such changes and modifications asObviously, exhaust from this cross ran within the true spirit and scopeof the inventicn.

What I claim as :new and desire to secure by Letters Patent oi theUnited states is:

l. An alternating current electric circuit breaker of the fluid blasttype comprising means defining an arcing chamber, a pair of relativelymovable contacts arranged to separate and draw an are within saidchamber, means including normally close-d valve means for supplying ablast of fluid to :an are drawn between said contacts upon separationthereof, and resilient means normally tending to open said valve means,said resilient means being magnetically restrained from opening saidvalve means by instantaneous values of current through the breaker inexcess of a predetermined value.

2. An alternating current electric circuit breaker of the fluid blasttype comprising means defining an arcing chamber, a pair of relativelymovable contacts arranged to separate and draw an are within saidchamber, means including normally closed valve means for supplying ablast of fluid to an are drawn between said contacts upon separationthereof, and resilient means normally tending to open said valve means,said resilient means being magnetically restrained from opening .saidvalve means by instantaneous values of current through the breaker inexcess of a predetermined value, said resilient means being efiectiv-eto open said valve means for instantaneous currents through "the breakerwhich are below a predetermined value.

3. An alternating current electric circuit breaker of the fluid blasttype comprising means defining :an arcing chamber, a pair of relativelymovable contacts arranged to separate and draw an are within saidchamber, means including normally closed valve means for supplying ablast of fluid to an arc drawn between said contacts upon separationthereof, resilient means normally tending to open said valve means, andmechanical restraining means normally arranged to prevent said resilientmeans from opening said valve means, said restraining means beingrendered ineiiectivc to prevent said resilient means from opening saidvalve means in response to opening movement of said contacts and saidresilient means bein magnetically restrained from opening said valvemeans by instantaneous values of current through the breaker in excessof a predetermined value.

a. An alternating current electric circuit breaker 'of the fluid blasttype comprising means defining an arcing chamber, a pair of relativelymovable contacts arranged to separate and draw an are within saidchamber, means including normally closed valve means for supplying ablast of fluid to an are drawn between said contacts upon separationthereof, resilient means normally tending to open said valve means, andmechanical restraining means normally arranged to prevent said resilientmeans from opening said valve means, said restraining means beingrenderedi-neffective to prevent said resilient means from opening saidvalve in response to opening movement of said contacts and saidresilient means being magnetically restrained from openin; :said valvemeans by instantaneous values of current through the breaker in excessof a predeter-minedvalue, said resilient means being eftective to opensaid valve means for instantaneous currents through the breaker whichare below a predetermined value.

5. An alternating current electric circuit breaker of the fluid blasttype comprising means defining an arcing chamber having an inlet and anoutlet, a pair of relatively movable contacts arranged to separatewithin said chamber, one of said contacts being hollow and beingarranged so as to define a pressure relieving passage for the escape ofpressure from within said chamber due to an are drawn between saidcontacts upon separation thereof, valve means normally closing saidinlet, resilient means normally tending to open said valve means, saidresilient means being magnetically restrained from opening said valvemeans by instantaneous values of current through the breaker in excessof a predetermined value, and means for supplying a blast of fluidthrough said inlet and into said arcing chamber in response to openingof said valve means.

6. An alternating current electric circuit breaker of the gas blast typecomprising means defining an arcing chamber having an inlet port and anoutlet port, a pair of relatively movable contacts arranged to separatein said chamber, one of said contacts being hollow so as to define apressure relieving passage for the escape of pressure from within saidchamber due to an are drawn between said contacts upon separationthereof, and means including current responsive valve means forsupplying a cross blast of gas to said chamber through said inlet portin response to an opening operation of the breaker,

said valve means being magnetically restrained in the closed position byinstantaneous currents through the breaker in excess of a predeterminedvalue and being biased toward the open position.

7. An electric circuit breaker of the gas blast type comprising meansdefining an arcing chamber having an inlet port and an outlet port, apair of relatively movable contacts arranged to separate in saidchamber, a movable one of said contacts being hollow so as to define apressure relieving passage for the escape of pressure from within saidchamber due to an are drawn between said contacts upon separationthereof, an operating mechanism operably related with said hollowcontact for imparting operating movement thereto, and means includingcurrent responsive valve means for supplying a cross blast of gas tosaid chamber through said inlet port rendered operable in response to anopening operation of the breaker, said valve means being magneticallyrestrained in the closed position by instantaneous currents through thebreaker in excess of a predetermined value and being biased toward theopen position.

8. An alternating current electric circuit breaker of the gas blast typecomprising means defining an arcing chamber having an inlet and anoutlet, a pair of relatively movable contacts arranged to separatewithin said chamber, valve means normally closing said inlet, aconductor in series with said contacts, said conductor forming twoparallel paths along a portion of its length, and a strip of insulatingmaterial interposed between said paths, one of said paths being fixed inposition and the other of said paths being operably related with saidvalve means and being stressed so as to tend to impart opening movementto said valve means, the magnetic attraction between said paths beingeffective to prevent opening of said valve means for instantaneouscurrents through the breaker in excess of a predetermined value andbeing ineffective to prevent opening of said valve means forinstantaneous currents through the breaker below a predetermined valueduring an opening operation of said contacts.

9. An alternating current electric circuit breaker of the gas blast typecomprising means defining an arcing chamber having an inlet and anoutlet, a pair of relatively movable contacts arranged to separatewithin said chamber, valve means normally closing said inlet, aconductor in series with said contacts, said conductor being split intotwo parallel parts along a portion of its length, and a strip ofinsulating material interposed between said parts. one of said partsbeing fixed in position and the other of said parts being resilient andoperably related with said valve means and being stressed so as to biassaid valve means toward the open position, the magnetic attractionbetween said parts being efiective to prevent opening or said valvemeans for instantaneous currents through the breaker in excess of apredetermined value and being inefiective to prevent opening of saidvalve means for instantaneous current through the breaker below apredetermined value during an opening operation of said contacts, andholding means for maintaining said valve means closed during ,only theinitial portion of an opening operation of the breaker.

10. An alternating current electric circuit breaker of the gas blasttype comprising a frame structure, means defining an arcing chamberhaving an inlet and an outlet, a pair of relatively movable contactsarranged to separate within said chamber, valve means normally closingsaid inlet, a conductor in series with said contacts, said conductorbeing split into two parallel parts along a portion of its length, astrip of insulating material interposed between said parts, and abushing of insulating material mounted on said frame and in which saidsplit conductor and said strip of insulating material are disposed, oneof said parts being fixed in position and the other of said parts beingresilient and operably related with said valve means and being stressedso as to bias said valve means open, the magnetic attraction betweensaid parts being effective to prevent opening of said valve means forinstantaneous currents through the breaker in excess of a predeterminedvalue and being ineffective to prevent opening of said valve means forinstantaneous current through the breaker below a predetermined valueduring an opening operation of said contacts.

11. An alternating current electric circuit breaker of the gas blasttype comprising a frame structure, means defining an arcing chamberhavsaid conductor being split into two parallel parts along a portion ofits length, a strip of insulating material interposed between saidparts, and a bushing of insulating material mounted on said frame and inwhich said split conductor and said strip of insulating material aredisposed, one of said parts being fixed-in position and the other ofsaid parts being operably related with said valve means and beingstressed so as to tend to impart opening movement to said valve means,the magnetic attraction between said parts being effective to preventopening of said valve means for instantaneous currents through thebreaker in excess of a predetermined value and being ineffective toprevent opening of said valve means for instantaneous current throughthe breaker below a predetermined value during an opening operation ofsaid contacts, and holding means for maintaining said valve means closedduring only the initial portion of an opening operation of the breaker.

12. An alternating current electric circuit breaker of the gas blasttype comprising means defining an arcing chamber having an inlet and anoutlet, a pair of relatively movable contacts arranged to separatewithin said chamber, valve means normally closing said inlet, resilientmeans normally tending to open said valve means, and mechanical holdingmeans normally arranged to prevent said resilient means from openingsaid valve means, said holding means being rendered ineffective toprevent said resilient means from opening said valve means in responseto opening movement of said contacts and said resilient means beingmagnetically restrained from opening said valve means by instantaneousvalues of current in excess of a predetermined value.

13. An alternating current electric circuit breaker of the gas blasttype comprising means defining an arcing chamber having an inlet and anoutlet, a pair of relatively movabl contacts arranged to separate Withinsaid chamber, one of said contacts being hollow and being arranged so asto define a, pressure relieving passage for the escape of pressure fromwithin said chamber due to an are drawn between said contacts uponseparation thereof, an operating mechanism operably related with saidhollow contact for imparting operating movement thereto, valve meansnormally closing said inlet, resilient means normally tending to opensaid valve means, and mechanical holding means normally arranged toprevent said resilient means from opening said valve means, said holdingmeans being rendered ineffective to prevent said resilient mean fromopening said valve means in response to opening movement of saidcontacts and said resilient means being magnetically restrained fromopening said valve means by instantaneous values of current in excess ofa predetermined value.

14. An alternating current circuit breaker including an electric bushingin the interrupting circuit, conductor stud structure disposed in saidbushing comp-rising parallel current paths including a rigid member anda resilient member, interrupting means including separable contacts fordrawing an arc to be extinguished, currentresponsive means forcontrolling the extinguishment of said are, said current-responsivemeans responding to the varying magnetic interaction between saidparallel current paths.

WILLIAM E. PAUL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,298,778 Thumim et a1 Oct. 13, 1942 2,428,482 Wilcox et a1Oct. 7, 1947 2,440,995 Wilcox May 4, 1948 2,456,965 Leitzel Dec. 21,1948 2,561,486 Thibaudat July 24, 1951

